This invention relates to internal combustion engines of the four cycle reciprocating type wherein a first down-stroke of a piston effects intake of working fluid following the preceding exhaust, followed by a first up-stroke of the piston that effects compression of said working fluid, followed by a second down-stroke of the piston as a result of combustion and expansion of the working fluid, and finally followed by a second up-stroke of the piston that effects exhaust and expending of said working fluid. Valves are usually employed to operate in timed relation to a crank shaft connected to the piston by connecting rods journaled thereto respectively, for example poppet or rotary or sleeve type valves, exclusively and not a combination of these known types of valves. There are of course, various advantages and disadvantages with these different types of valves, the poppet type being most widely used and highly developed and operated by cams driven in timed relation to the crank shaft. However, rotary valves have not been too successful where hot gases are concerned, but they have advantages in directing fluid selectively via a multiplicity of ports. It is a general object of this invention to combine the advantageous features of the poppet valve and rotary valve so that they are cooperative in providing unobvious results. With this invention, both the intake and exhaust of the working fluid are blown and the fuel is injected, and all to the end that there is supercharged induction and the after burning of exhaust. It will be seen therefore, that this engine has both the advantage of blown intake and exhaust.
The conventional engine requires separate poppet valves for intake and exhaust, operated in timed relation to rotation of the engine crank shaft so that the intake valve opens only on the first mentioned down-stroke and so that the exhaust valve opens only on the last mentioned up-stroke. It is an object of this invention to advantageously handle both intake and exhaust with a single poppet valve, utilizing the sequence of the exhaust being followed by the intake, characteristic of four cycle engines. With the present invention, a single poppet valve is opened for exhaust and remains open for intake, all of which is made possible by combining therewith a rotary valve that controls intake and/or diverts blown air between induction and exhaust. During the intake down-stroke, the rotary valve directs blown air through the opened poppet valve, after which the rotary valve diverts blown air into the exhaust when the poppet valve is closed during the compression stroke. The poppet valve remains closed throughout the compression and power strokes during which the rotary valve remains open from induction into the exhaust. During the exhaust up-stroke the rotary valve closes off the blown air to both intake and exhaust while diverting the exhaust from the opened poppet valve. As with conventional engines, the valve timing of this invention is at one half crank shaft speed, it being understood that opening and closing of said poppet valve is related to the top dead center and bottom dead center positions of the crank shaft as with conventional engines of the reciprocating piston type.
It is imparitive for compression of working fluids that the valves close tightly, and it is for this reason that poppet valves have been so widely used for this purpose. In practice, there is no problem in seating poppet valves tightly. However, with rotary valves sealing is a problem as sliding fits are involved. To the contrary sealing is not a problem with this invention, since the subject rotary valve is employed for diverting blown air used advantageously for both intake and exhaust. Accordingly, it is an object of this invention to cooperatively employ the seating advantages of the poppet valve with the diverting advantages of the rotary valve, in an engine wherein the working fluids are induced by blower means.
Heretofore, the use of air pumps and blowers have been relegated to either that of supercharging or exhaust scavenging, and in both by means of a single pump or blower. That is, both induction and exhaust blowers have been widely used for their respective advantages, but not as a single blower adapted by valve means to serve both purposes of supercharging and scavenging. To this end therefore, it is an object of this invention to provide valve means that diverts blower air between the engine intake and exhaust. With the rotary valve hereinafter described, the conventional intake and exhaust poppet valves (two valves) can be employed; or preferably as shown, a single dual purpose poppet valve is employed for both intake and exhaust.
Feasibility of carburetion is an object of the present invention, although not the preferred form thereof. In the event that carburetion is desired, the rotary valve is made of the duplex or double type with separated channels diverting the intake and exhaust and to the end that carburetion induction air enters the poppet valve plenum and cylinder without contacting the exhaust, and the exhaust passing through said plenum without contacting the intake; all of which is made possible by the diverting capabilities of the rotary diverter valve operating in cooperatively timed relationship with the cylinder controlling poppet valve.
Fuel injection has qualities superior to carburetion, and with this engine operated to share blower induction with blower scavenging, said fuel injection or the equivalent is preferred. It would be obviously prohibitive to blow the exhaust with carbureted air, when after burning of the exhaust combustibles is desired. Therefore, it is an object of the preferred form of this invention to fuel inject in combination with a rotary diverter valve and cylinder controlling poppet valve. It is characteristic of this invention that the poppet valve controls the cylinder intake, compression and exhaust, while the rotary valve diverts blower air between intake and exhaust; and all of which requires timed injection of fuel during the intake stroke or cycle of engine operation. As will be described, the valve relationships are conducive to fuel injection without any adverse effect upon the sharing of the air induction with exhaust scavenging.
It is an object of this invention to provide a compatible arrangement of dissimilar rotary and poppet valves, in an internal combustion engine of the four cycle type. Conventional valve gear involves cam shaft operated tappets or lifters, conducive to poppet valve operation; while rotary valves involve gearing or the like. With the present invention the timed sequence of rotary and poppet valve operation are both compatible with four cycle operation, and both operated at one half engine speed of rotation. As will be described with respect to the several embodiments of this invention, these two dissimilar but cooperatively related valves are driven together or one from the other, as by gears or chains or belts and/or the poppet valve by means of tappets or rockers; all of which are directly driven from the engine crank shaft. Further, the valve gear combination as hereinafter disclosed is adaptable to multicylinder engines with a single induction blower and manifold characteristically coordinated with a single exhaust after burner manifold.